Luther Sage, (Yellowstone Kelly), was one of the most notable frontiersmen who helped to form the West. Spending several years scouting and hunting the area around the Yellowstone and Missouri rivers, he frequently visited the Reed & Bowles Trading Post near what is now Lewistown.
He also loved the terrain of the Musselshell River. Kelly was lead scout for Nelson Miles, a veteran of three wars, and a trader and hunter. After a life of adventure and exploration, Kelly died in 1928 at age 79. He is buried at Kelly Mountain which is now Swords Rimrock Park in Billings, Montana.